11-keto-beta-boswellic acid (KBA) is one of the most active components derived from the resin of Boswellia serrata, commonly known as frankincense. There is scientific evidence supporting its use in maintaining respiratory health, particularly via its anti-inflammatory effects. Several in vitro and animal studies, as well as some small clinical trials, show that KBA and related boswellic acids inhibit 5-lipoxygenase, an enzyme involved in leukotriene synthesis. Leukotrienes play a significant role in the inflammation and constriction of airway passages, which are key features in conditions such as asthma and chronic bronchitis.

Human studies, though limited, suggest that Boswellia serrata extracts (which contain KBA) may reduce symptoms and improve lung function in patients with asthma. For example, a 1998 randomized, double-blind, placebo-controlled trial reported clinical improvements in 70% of asthma patients treated with Boswellia extract versus 27% in the placebo group.

However, it is important to note that most studies use whole extracts containing several boswellic acids, not isolated KBA, and sample sizes are generally small. Thus, while the mechanistic rationale and preliminary clinical findings are promising, large-scale, high-quality clinical trials are still needed to confirm the efficacy and safety of KBA for bronchial support.